Salpausselkä

a system of three hilly terminal morainic ridges in southern and southeastern Finland, which extend parallel to each other along the northern shores of the Gulf of Finland and Lake Ladoga. The Salpausselkä is 550 km long, and the distance between its ridges is 30–50 km. With elevations to 247 m, the ridges rise 70–100 m above the adjacent plains. They were formed during the melting of the last ice sheet. They are composed of sand and rubble deposits and glacial and glaciofluvial deposits and are covered primarily with taiga forests. Several rivers, including the Imatra, form rapids and waterfalls as they break through the Salpausselkä.